1. Field
An embodiment of the invention relates to a solution for use in an electroless deposition process and to methods of preparing and using the solution.
2. Background Information
Electroless deposition processes are widely used to deposit metals on surfaces. In an electroless deposition process a substrate or workpiece object having a surface to be coated may be introduced into a bath containing an electroless deposition solution. The solution often contains a soluble metal salt and a reducing agent, and may contain other chemical additives, such as complexing agents, buffers, bath stabilizers, and rate promoters.
Once introduced into the bath, metal is deposited on the surface based on an electroless deposition process. In a representative electroless deposition process an oxidation-reduction (redox) reaction occurs in which an oxidation number of metal ions of the metal salt are reduced while an oxidation number of the reducing agent is increased. The reaction often proceeds as an autocatalytic, or continuing by itself, chemical reduction at catalytically active sites of the surface. The reaction generally converts the metal ions into a non-ionic metallic state deposited on the surface.
Potential advantages of such an electroless deposition process include uniform layer thickness and ability to deposit metal layers on irregular shaped objects including in holes, recesses, narrow trenches, and other high aspect ratio structures. For these and other reasons, electroless depositions are used widely in industry to form interconnect structures for microelectronic devices, reflective layers for mirrors, metallic coatings for micro-electromechanical devices (MEMS), and more generally to provide metallic layers for workpiece objects such as manufactured parts.